That's a great example of context. You acted as was expected of you, and knew that noone will interrupt no matter what. It is inticing to think that the solution is to change your mannerism, but sadly (?) life isn't a never ending funeral. I've tried it myself, of course, but in the end it's about building confidence no matter the circumstances. That even if you stutter you'll still be able to reach your goal. Some won't stand in your way, some will. Think about it enough, about human nature, and repeat your findings before stressful encounters. Show your brain it's in capable hands. Start small, see if it's working. If it does sometimes, don't beat yourself up when it doesn't. remind yourself that it is possible.